simulation lemma
Incrementality Bidding via Reinforcement Learning under Mixed and Delayed Rewards Appendix AFormal Definition of Inhomogeneous Poisson Process
The inhomogeneous Poisson (point) process is a Poisson point process with a Poisson parameter set as some time-dependent function r(ฯ). Let N(a,b) represent the number of points of inhomogeneous Poisson process with intensity function r(t) occurring in the interval [a,b], then the probability of n points existing in the interval [a,b] is given by, P(N(a,b) = n) ฮ(a,b)n n! In this paper, the points mean the conversions and the time-dependent intensity function r() is defined in Eq. (2) and it depends on the realization of the conversions and parameter ฮธ. Suppose X1, Xn are independent, mean-zero, subexponential random variables, and a = (a1,,an) is an ndimensional constanst vector. We first introduce the main idea of the the PAMM algorithm.
Structure of the supplementary material
Appendix B provides the proofs for the results of the basic setting presented in Section 3. Appendix C provides the proofs and additional discussion for the results of the concave-convex setting presented in Section 4. Appendix F provides auxiliary concentration lemmas useful for the derivation of our results. RL, is presented at Algorithm 1. In this setting, unlike basic setting, objective and constraints are not linear. Similar to before, expressing this program based on occupation measures provides a convex program. We define the bonus-enhanced cMDP, i.e.
An Optimal Tightness Bound for the Simulation Lemma
We present a bound for value-prediction error with respect to model misspecification that is tight, including constant factors. This is a direct improvement of the "simulation lemma," a foundational result in reinforcement learning. We demonstrate that existing bounds are quite loose, becoming vacuous for large discount factors, due to the suboptimal treatment of compounding probability errors. By carefully considering this quantity on its own, instead of as a subcomponent of value error, we derive a bound that is sub-linear with respect to transition function misspecification. We then demonstrate broader applicability of this technique, improving a similar bound in the related subfield of hierarchical abstraction.
Explicit Explore, Exploit, or Escape ($E^4$): near-optimal safety-constrained reinforcement learning in polynomial time
Bossens, David M., Bishop, Nicholas
In reinforcement learning (RL), an agent must explore an initially unknown environment in order to learn a desired behaviour. When RL agents are deployed in real world environments, safety is of primary concern. Constrained Markov decision processes (CMDPs) can provide long-term safety constraints; however, the agent may violate the constraints in an effort to explore its environment. This paper proposes a model-based RL algorithm called Explicit Explore, Exploit, or Escape ($E^{4}$), which extends the Explicit Explore or Exploit ($E^{3}$) algorithm to a robust CMDP setting. $E^4$ explicitly separates exploitation, exploration, and escape CMDPs, allowing targeted policies for policy improvement across known states, discovery of unknown states, as well as safe return to known states. $E^4$ robustly optimises these policies on the worst-case CMDP from a set of CMDP models consistent with the empirical observations of the deployment environment. Theoretical results show that $E^4$ finds a near-optimal constraint-satisfying policy in polynomial time whilst satisfying safety constraints throughout the learning process. We discuss robust-constrained offline optimisation algorithms as well as how to incorporate uncertainty in transition dynamics of unknown states based on empirical inference and prior knowledge.